This free tool from Autodesk improves the quality and the information content of DWG files generated from the Revit model and helps overcome a number of limitations of the built-in DWG Export feature
Define Layer Standards
"Break down" a layer into well defined components to make the process of assigning a layer a whole lot easier.
Leverage Shared Coordinates to create geo-referenced drawings by exporting sheets in your Revit model.
Create blocks with attributes from families and annotations
Create drawings for AutoCAD based facilites management systems directly from the Revit model.
The Enhanced DWG Exporter is free to download and use, just select your Revit version and get started.